The present invention concerns citrus press devices which are to be mounted on a so-called kitchen robot device which, by fixing various tools, such as knives, grater discs, mincer discs, etc. on the drive shaft of an electric motor permits various culinary operations to be performed. More particularly, the present invention relates to devices which are to be mounted on apparatus of this type in which the motor can only be put into operation when the cover is in a closure position, the closing of the cover itself assuring in certain cases the actuation of the motor. Apparatus of this type is described in French Patent Specifications Nos. 71.27039 and 77.08648. There is a need for such precautions since the motors used can turn at up to several thousand revolutions per minute, which gives rise to a certain danger.